Transcript for Hundreds of Firefighters Deployed Near Yosemite to Fight Raging Wildfires.

We do begin with an american treasure threatened pie that fierce and growing wildfire tonight. Yosemite park. This is the screen on the ground. The ancient sequoias, fire trucks rushing through valleys of fire and just listen tonight. The sound of that wildfire raging out of control, hundreds of firefighters now deployed. New evacuations under way. That fire one of at least 50 burning in the west tonight. Where yosemite is declaring a state of emergency. Neal karlinsky is on the front lines for us and he leads us off tonight. Good evening. Reporter: Good evening from the south side of this fire. These are not clouds behind me. This is smoke. You can get a sense of the scope and size of this fire. The plume shooting up there and the fire builds up and gets smaller again. As the fire is fought mainly by the air. At the yosemite rose bed and breakfast built for the thousands who flock to its untouched beauty each year, they're making their last stand. The fire is coming over the hill straight at them and the owner in his bulldozer is making plans with the fire team. Give me the signal and I can make lapse around the house without a problem. Reporter: Just down the road this man has another fire team at his house, staring down an intense aerial fire fight to stop the flames before they burn through his property. Are you sticking here throughout? Absolutely. Protect what I can as long as i can. Reporter: The wind has caused rapidly changing conditions as we found out first hand. It shot up again, the flames did. While shooting this material in the fire zone -- whoa! A chunk of flaming tree big enough to seriously hurt someone fell near our car. It's unusually bad right now i know though the wildfire numbers are down nationwide. They're way up in california where there have been nearly 40 percent more fires than last year. Hundreds more caused by lightning within just days. We found homeowners packed up, ready to leave if they have to. If we lose it all, we have a great insurance policy, so. Hopefully it won't come to that. We'll start all over again. Reporter: The fire is not threatening anymore homes right now but its continuing to grow. It has tripled in size since yesterday. They've's got a real fight on their hands. That dark smoke behind you, neil. Thanks to you. Ginger zee is tracking this fire for us. You were telling me the fire is close to yosemite and the park is not in the clear yet. Not at all. They have the try foilage. It's all of the west. 50 large wildfires in nine states out west dealing with this. Lightning as neil mentioned a huge issue. That's why we have red flag warnings. I want to show you who has this. See that low pressure system. That's part of the issue. Kicking off gusty winds and over 4400 lightning strikes starting 45 new fires just in california.

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Forest Fires at Yosemite Force Evacuations

Wildfires in remote area of park that started Saturday forced road and park closures.